The present invention relates to a longitudinal drawing device for synthetic films.
Longitudinal film drawing devices used in industry usually comprise, from upstream end downstream (referring to the direction of travel of the film that is to be drawn):
a set of preheating rolls, the number and diameter of which are chosen according to the material of which the film that is to be drawn is made, according to the thickness of this film and according to the desired production rate;
a drawing unit exhibiting a succession of cylinders, the first cylinders being driven at relatively low speed and the next cylinders being driven at a faster speed, so as to draw the film between successive cylinders driven at different increasing speeds;
a thermostabilization unit, the function of which is to allow the thermal expansion and stabilization of the film before the subsequent transverse drawing of this film.